Solved Example on Carson’s Rule for Bandwidth Calculation

A broadcasting station has a highest modulating frequency fm = 10kHz and a maximum frequency deviation fd =4 kHz. Calculate the bandwidth required using Carson’s Rule.

Using Carson’s Rule formula:

B = 2(fm + fd)

B = 2(10+4)

B = 2×14

B = 28kHz

Therefore, the required bandwidth for the broadcasting station is 28kHz.

Carson’s Rule for Bandwidth Calculation

Carson’s Bandwidth Rule is an important concept in Electronics and Communication Engineering. This rule is used for the calculation of FM modulation bandwidth or occupancy for the FM signal. Let’s say you are designing an FM system on satellite, you will need to make sure that your signal is not cross-talking into other signals on the system.

FM creates modulation sidebands that in theory extend to infinite bandwidth. These sidebands consist of Bessel Functions of any order. However, practically the band occupancy of an FM-modulated carrier solely needs to count the Bessel Function sidebands of necessary amplitude. Carson’s Rule is used to calculate this bandwidth.

This article will incorporate definitions and basic principles of Carson’s Rule followed by the important applications, merits, demerits, and at last a solved example to enhance our understanding of the rule.

Table of Content

  • Carson’s Rule
  • Working Principle
  • Carson’s Rule Table
  • Derivation
  • Special Cases
  • Applications
  • Solved Example
  • Advantages and Disadvantages

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What is Carson’s Rule?

Carson’s Bandwidth Rule is used for the calculation of FM modulation bandwidth or occupancy for the FM signal which is an important concept in Electronics and Communication Engineering. Given bellow is the statement for the Carson’s Rule....

Working Principle of Carson’s Bandwidth Rule

This rule follows the experimental conclusion that established that there is a finite number of side bands around the carrier frequency, of which about 98% contain the total power of an FM signal, Rest of the Side Bands in the frequency spectrum contain about 2%. Thus, 2% of the total power can be sacrificed to reduce the bandwidth of an FM system to a practically feasible limit. The 2% power loss is acceptable in exchange for the received enhancement. Infinite bandwidth is required for Signal and its total power to be transmitted....

Carson’s Rule Table

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Derivation of Carson’s Bandwidth Rule

In deriving the equation for an FM wave, it was assumed, for the sake of simplicity, that the carrier signal’s amplitude is one (Ec = 1).The powers contained in the frequency components, assuming the resistance of the transmitting antenna is 1 ohm, are calculated as:...

Special Cases of Carson’s Bandwidth Rule

Case 1. fd << fm (NBFM)...

Applications of Carson’s Rule

Radio Broadcasting: Carson’s Rule figures out how much bandwidth amplitude-modulated (AM) radio stations need. The best possible transmission quality and spectrum use can be guaranteed by broadcasters by precisely calculating the bandwidth. Wireless Communication Systems: The determination of how much bandwidth is needed to send signals over different wireless channels in wireless communication is helped by Carson’s Rule. This determination enables engineers to design and develop cost-efficient Wireless Communication Systems. Radar Systems: In Radar Systems, We employ Carson’s rule to determine the required bandwidth as the transmission and reception of signals in radar systems depend on exact bandwidth estimations. Television Broadcasting: Broadcasters may provide viewers with high-quality television programs by precisely predicting the bandwidth required using Carson’s rule. Satellite Communication: Carson’s Rule provides the efficient distribution of bandwidth for data transmission between ground stations and satellites. This increases satellite efficiency....

Solved Example on Carson’s Rule for Bandwidth Calculation

A broadcasting station has a highest modulating frequency fm = 10kHz and a maximum frequency deviation fd =4 kHz. Calculate the bandwidth required using Carson’s Rule....

Advantages and Disadvantages of Carson’s Rule for Bandwidth Calculation

There are some Advantages and Disadvantages of Carson’s Rule for Bandwidth Calculation given below :...

Conclusion

Carson’s rule for bandwidth computation describes the estimated bandwidth needs of communication system components for a carrier signal that is frequency modulated across a continuous or large frequency range rather than a single frequency. We can use it different areas like for radio and television broadcasting, radar system, satellite communications, etc....

Carson’s Rule for Bandwidth Calculation – FAQs

Is Carson’s Rule still relevant?...